Preparation of hollow hierarchical porous CoMgAl-borate LDH ball-flower and its calcinated product with extraordinary adsorption capacity for Congo red and methyl orange

• Published in: Applied clay science Vol. 207; p. 106093
• Main Authors: Miao, Jing, Zhao, Xiaojun, Zhang, Yu-Xiu, Lei, Zhong-Li, Liu, Zhi-Hong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.06.2021
• Subjects: Adsorption performance; Borate anions intercalated layered double hydroxides; Congo red and methyl orange pollutant; Hollow hierarchical porous structure; Borate anions intercalated layered double hydroxides; Hollow hierarchical porous structure; Adsorption performance; Congo red and methyl orange pollutant
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2021.106093

Three-dimensionally ordered hollow borate anions intercalated CoMgAl-LDH ball-flower with hierarchical porous structure have been prepared by using zeolitic imidazolate framework-67 (ZIF-67) as a self-sacrificing template. After calcination it, the obtained CoMgAl-borate LDO can inherit the hollow hierarchical porous structure. Its unique structure has the merits of low density, large specific surface area, large pore size distribution and short diffusion pathway, which should be beneficial to the adsorption of larger dye molecules. The maximum uptake capacity of CoMgAl-borate LDO can even reach as high as 1493.3 mg g−1 for Congo red (CR) and 990.1 mg g−1 for methyl orange (MO) owing to the hierarchical hollow porous structure, the “memory effect”, electrostatic interactions, hydrogen bond and ion exchange between anionic dye and cationic adsorbent surface, surpassing those of most previously reported LDH-based adsorbents. The entire adsorption processes for CR and MO follow Langmuir isotherm and pseudo-second-order kinetics model. Moreover, the removal efficiency of CoMgAl-borate LDO can still reach 86.5% for CR and 84.3% for MO after recycling five times, indicating that CoMgAl-borate LDO is a very promising high-efficiency adsorbent. This work not only demonstrates that CoMgAl-borate LDO is a very green and efficient adsorbent for the removal of anionic dyes from wastewater, but also provides a strategy for the rational design and development of hollow nanostructures. [Display omitted] •Hollow CoMgAl-borate LDH ball-flowers with hierarchical porous structure have been prepared.•The morphology well retained CoMgAl-BLDO were obtained by calcination of CoMgAl-BLDH.•CoMgAl-BLDO exhibit excellent adsorption performances for CR or MO pollutant.•It can be as a very promising high-efficiency adsorbent for wastewater remediation.•This study shed light on the rational design and fabrication of hierarchical hollow porous adsorbent.